Strand Underpass

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It is built within part of the former Kingsway tramway subway. The original tramway tunnel was 20 ft (6.6 m) wide and allowed bi-directional flow because of the fixed rails and relatively narrow width of the trams; however, the new road tunnel was only 17 ft (6.25 m) wide, and consequently only northbound traffic was permitted, because of the side clearances required. The headroom is only 12 ft 6 in (3.75 m) due to the tunnel having to pass beneath the bridge abutment by means of a 1:12 gradient. An electronic 'eye' alerts drivers of tall vehicles and diverts them to an 'escape route' to the left of the entrance. However, high vehicles do still try to go through and so get stuck occasionally. There is also a little known Savoy garage exit of the Old Kingsways tram which was originally incorporated into the Strand underpass but is now closed.

Underground, the new underpass is constructed in a concrete box within the former tram tunnel; the road surface, however, is at the original track level. At the northern end of the tunnel, the road rises to the surface on a new carriageway supported by metal pillars. This passes through the site of the former Aldwych tramway station, but because of the greater width requirement, 27 trees and some pavement had to be removed for it to be constructed.